JP2015103863A - Network management system, communication system, and network management method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish push-type communication that is performed by allocating an IP address to a communication terminal, even in the case where the communication terminal cuts off connection to a network.SOLUTION: When an IP address is assigned to a communication terminal 20 to be connected to an access point AP1, an authentication module 12 of a network 10 stores the IP address in an IP address history DB 13 so as to identify the communication terminal 20 to which the IP address is assigned. When the communication terminal 20 is disconnected from the access point AP1 and re-connected after a lapse of a disconnection term, the authentication module 12 re-assigns the IP address stored in the IP address history DB 13. The IP address to be assigned to one communication terminal 20 is made identical before and after the disconnection term by this re-assignation. A data transfer module 14 transfers a communication packet in push-type communication that is generated during the disconnection term, to the communication terminal 20 after the re-assignation of the IP address.

Description

  The present invention relates to management of push-type communication.

  A communication terminal such as a smartphone or a mobile phone terminal may switch a connection destination (for example, an access point) in a network depending on a communication service to be used. However, in this communication service, when push type communication using an IP (Internet Protocol) address as the destination address is used, the IP address is discarded after the communication terminal disconnects from the corresponding connection destination. Therefore, the push type communication may not be established. In the communication performed by constructing a communication path so that a relay device (proxy) is interposed between the server application and the client application, when the communication path is switched in the middle, Patent Document 1 It is disclosed that a proxy accumulates communication contents transmitted by an application and transmits accumulated information when communication becomes possible. Patent Documents 2 and 3 disclose that a communication terminal used by a user is led to automatically determine a connection destination of data communication and connect.

JP 2002-64562 A JP 2009-49897 A JP-T-2006-262131

The invention described in Patent Document 1 is intended to guarantee the continuity of communication services, and is premised on switching communication paths in the middle without ending communication. For this reason, according to the invention described in Patent Document 1, it is considered that push-type communication can be established even if communication is temporarily disabled during switching of the communication path. However, in the invention described in Patent Document 1, when the communication terminal terminates communication and disconnects from the network, the IP address is discarded when triggered by the disconnection. Therefore, the IP address before the disconnection is used. Push-type communication cannot be established. The inventions described in Patent Documents 2 and 3 perform switching of the connection destination led by the communication terminal, and it is difficult for the communication terminal side to always grasp whether or not there is push-type communication from the network side.
Therefore, an object of the present invention is to establish push-type communication performed by assigning an IP address to a communication terminal even when the communication terminal disconnects from the network.

  In order to solve the above-described problem, a network management system according to the present invention is a network management system that manages communication performed via an access point provided in a predetermined network, and a communication terminal is connected to the access point. In this case, an IP address that identifies a transfer destination of a communication packet is issued, and the first assignment unit assigned to the communication terminal and the IP address assigned by the first assignment unit are assigned to the communication to which the IP address is assigned. A storage unit that stores the terminal in an identifiable manner, and the communication terminal that has disconnected from the access point and resumed the connection after a non-connection period, the IP stored by the storage unit for the communication terminal A second allocation unit that performs reallocation of an address and an IP address allocated by the first allocation unit as a destination address Shin packet, if they occur in the non-connection period, after the second assignment unit makes a reassignment of the IP address, and a transfer processing unit for transferring the communication packet.

In the network management system of the present invention, the network management system further includes a buffer processing unit that buffers communication packets generated during the non-connection period, and the transfer processing unit receives the IP address reassigned by the second allocation unit as a destination The communication packet having the address may be transferred from the buffer to the communication terminal.
In this invention, when the capacity of the buffered communication packet is equal to or greater than a threshold, the connection control unit for transmitting a control signal for resuming the connection to the communication terminal, the transfer processing unit, The buffered communication packet may be transferred after the connection is resumed according to the control signal.

  In the network management system of the present invention, when the connection is disconnected, the state of the connection is changed to the preservation state, and when a communication packet is generated during the non-connection period, the state is returned from the preservation state. A transfer control unit may be provided, and the transfer processing unit may transfer the communication packet after returning from the preservation state.

  A communication system of the present invention includes any one of the network management systems provided in the network, and a communication terminal connected to the access point and communicating with the network.

  The network management method of the present invention is a network management method for managing communication performed via an access point provided in a predetermined network, and when a communication terminal is connected to the access point, a transfer destination of a communication packet is set. Issuing an IP address to be specified and assigning it to the communication terminal; a storage unit for storing the assigned IP address so that the communication terminal to which the IP address is assigned can be identified; and the communication terminal to the access point And when the connection is resumed after a non-connection period, a step of reassigning the stored IP address to the communication terminal, and a communication packet having the assigned IP address as a destination address If it occurred during the non-connection period, the IP address was reassigned In, and a step of transferring the communication packet.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where a communication terminal cut | disconnects the connection to a network, push type communication performed by assigning an IP address to the said communication terminal can be materialized.

The figure which shows the whole structure of the communication system of 1st Embodiment of this invention. The block diagram which shows the structure of the network of the embodiment. The figure which shows the structural example of the IP address log | history of the embodiment. Explanatory drawing of the relationship between the connecting point of the communication terminal of the embodiment, and the flow of a communication packet. The sequence diagram which shows the flow of the process performed with the communication system of the embodiment. The sequence diagram which shows the flow of the process performed with the communication system of the embodiment. The sequence diagram which shows the flow of the process performed with the communication system of the embodiment. The figure which shows the structural example after the update of the IP address log | history of the embodiment. The block diagram which shows the structure of the network of 2nd Embodiment. The sequence diagram which shows the flow of the process performed with the communication system of the embodiment. The sequence diagram which shows the flow of the process performed with the communication system of the embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram showing an overall configuration of a communication system 1 according to the first embodiment of the present invention. As shown in FIG. 1, the communication system 1 includes a network 10 and a communication terminal 20. The network 10 is a wireless communication network here, and includes a plurality of base stations, a plurality of exchanges, a group of communication nodes such as access points AP1 and AP2, and a communication line connecting these communication nodes to each other. The access point AP1 is an access point to which the communication terminal 20 is connected in order to communicate with the first server 30. The access point AP2 is an access point to which the communication terminal 20 is connected in order to communicate with the second server 40.

  The network 10 is connected to the first server 30 via the communication line L1. The first server 30 is a computer device that functions as a server of a client-server system. Here, the first server 30 is an ISP (Internet Services Provider) server and is a server device managed by the provider. The first server 30 accepts remote access from the communication terminal 20 and provides a predetermined service to the communication terminal 20 by performing data communication with the communication terminal 20. The service provided by the first server 30 is a service that accompanies data communication with the communication terminal 20, such as an Internet connection service or a mail service that provides an email storage area. However, the specific content of the service provided by the first server 30 is not particularly limited.

  The network 10 is connected to the second server 40 via the communication line L2. The second server 40 is a computer device that functions as a server of a client-server system. Here, the second server 40 is a company server installed in a company to which the user of the communication terminal 20 belongs. The second server 40 receives remote access from the communication terminal 20 and performs data communication with the communication terminal 20. The communication line L2 is, for example, a dedicated line or an Ethernet (registered trademark), and is a communication line isolated from the communication line L1. That is, the communication line L2 is a communication line (that is, a closed network) for the communication terminal 20 and the second server 40 to perform closed communication.

The communication terminal 20 is a communication terminal that communicates by connecting to the network 10 (in this case, wireless connection). The communication terminal 20 is a smartphone here, but may be a communication terminal such as a mobile phone terminal, a tablet terminal, a notebook computer, or a PDA (Personal Digital Assistant). When connecting to the first server 30, the communication terminal 20 transmits a connection request signal specifying an access point name (APN: Access Point Name) specifying the access point AP 1 to the network 10. When connecting to the second server 40, the communication terminal 20 transmits a connection request signal designating an APN that identifies the access point AP2 to the network NW. The APN is an example of connection destination information that identifies a connection destination of the communication terminal 20.
In FIG. 1, only one communication terminal 20 is shown, but there are actually more communication terminals 20. 1 shows only one each of the first server 30 and the second server 40, but there may be two or more each.

FIG. 2 is a block diagram showing the configuration of the network 10. FIG. 2 is a block diagram of a network management system that manages communications performed via the access point AP1 in the network 10.
The network 10 includes a connection control module 11, an authentication module 12, an IP address history DB (Data Base) 13, a data transfer module 14, and a gateway device 15. Each module of the connection control module 11, the authentication module 12, and the data transfer module 14 may be realized by any of hardware resources (for example, a server device), software resources, and combinations thereof. The IP address history DB 13 is a database realized by a storage device such as a hard disk.

The connection control module 11 (an example of a connection control unit) is a module that governs control related to the connection between the access point AP1 and the communication terminal 20. For example, the connection control module 11 establishes a communication path between the access point AP1 and the communication terminal 20, connects the two, or disconnects the connection.
In addition, the connection control module 11 realizes a function corresponding to the storage unit 111. The storage unit 111 stores the IP address assigned to the communication terminal 20 (for example, IPv4 or IPv6) as an IP address history in the IP address history DB 13 by making the communication terminal 20 identifiable. The IP address is an address that specifies a transfer destination of a communication packet (that is, communication data) to the communication terminal 20 in the network 10. The connection control module 11 transfers the communication packet supplied from the data transfer module 14 or the gateway device 15 to the communication terminal 20 according to the IP address specified as the destination address in the communication packet.

The authentication module 12 is a module for authenticating the communication terminal 20. Although the specific method of this authentication is not particularly limited, the authentication module 12 authenticates the communication terminal 20 based on a subscriber information database (not shown) in which information on subscribers to the communication service is registered.
In addition, the authentication module 12 implements functions corresponding to the first assignment unit 121 and the second assignment unit 122. When the communication terminal 20 is connected to the access point AP1, the first assignment unit 121 issues an IP address and assigns the IP address to the communication terminal 20. The first assigning unit 121 assigns an IP address to the communication terminal 20 so that two or more communication terminals 20 overlap at the same time. The first assigning unit 121 does not assign the IP address stored in the IP address history DB 13 to the communication terminal 20. The second assigning unit 122 reassigns an IP address to the communication terminal 20 when the communication terminal 20 disconnects from the access point AP1 and resumes connection (that is, reconnects) after a non-connection period. Do. The second assigning unit 122 acquires the IP address saved by the saving unit 111 from the IP address history DB 13 and reassigns the IP address to the communication terminal 20.

The IP address history DB 13 is a database that stores the IP address history saved by the connection control module 11. FIG. 3 is a diagram illustrating a configuration example of the IP address history stored in the IP address history DB 13.
As shown in FIG. 3, the IP address history DB 13 stores an IP address history in which an IP address is associated with a terminal identifier that uniquely identifies the communication terminal 20 to which the IP address is assigned. The terminal identifier is an identifier for identifying each of the communication terminals 20, and here is a telephone number assigned to the communication terminal 20. It is assumed that the terminal identifier is also registered in the subscriber information database referred to by the authentication module 12.
Of the IP address histories stored in the IP address history DB 13, those that have not been read for a predetermined period or longer may be deleted from the IP address history DB 13 by the authentication module 12.

  The data transfer module 14 is a module that transfers the communication packet supplied from the gateway device 15 to the communication terminal 20. The data transfer module 14 implements functions corresponding to the buffer processing unit 141 and the transfer processing unit 142. The buffer processing unit 141 buffers a communication packet generated during a period in which the communication terminal 20 is not connected to the network 10 in a buffer (not shown). The transfer processing unit 142 transfers the communication packet buffered by the buffer processing unit 141 to the communication terminal 20 at a predetermined timing according to the destination address specified by the communication packet. Specifically, when a communication packet having the IP address assigned by the first assigning unit 121 as the destination address occurs during the non-connection period, the transfer processing unit 142 causes the second assigning unit 122 to After the IP address is reassigned, the communication packet is transferred.

  The gateway device 15 is a relay device that relays data exchanged between the network 10 and the communication line L1 while performing protocol conversion. The gateway device 15 transfers the communication packet related to the push communication received from the first server 30 to the communication terminal 20 or the data transfer module 14.

In the present embodiment, when the first server 30 transmits a communication packet in push-type communication to the communication terminal 20, the communication packet is immediately transferred to the communication terminal 20 by the access point to which the communication terminal 20 is connected. There are cases where transfer is possible and cases where transfer is not possible.
FIG. 4 is an explanatory diagram of the relationship between the connection destination of the communication terminal 20 and the flow of communication packets for push-type communication. As shown in FIG. 4A, when the communication terminal 20 is connected to the access point AP1, the network 10 transfers the communication packet pd received from the first server 30 to the communication terminal 20 via the access point AP1. To do. On the other hand, as shown in FIG. 4B, when the communication terminal 20 is not connected to the access point AP1, the network 10 cannot transfer the communication packet pd received from the first server 30 to the communication terminal 20. . For this reason, the network 10 holds the transfer of the communication packet pd and transfers the held communication packet pd after the communication terminal 20 connects to the access point AP1.

5 to 7 are sequence diagrams showing the flow of processing executed in the communication system 1. Below, the flow of the process regarding the communication between the communication terminal 20 and the 1st server 30 which performs push type | mold communication is demonstrated. Before the process described below, the IP address history DB 13 is assumed to have the configuration described with reference to FIG.
First, the communication terminal 20 transmits a connection request signal designating an APN that specifies the access point AP1 to the network 10 (step S1). This connection request signal includes a terminal identifier assigned to the communication terminal 20.
Before transmitting the connection request signal, the communication terminal 20 is either connected to the access point AP2 or not connected to any of the access points AP1 and AP2.

  The connection control module 11 confirms the IP address history stored in the IP address history DB 13 based on the received connection request signal (step S2). Specifically, the connection control module 11 checks whether the IP address associated with the terminal identifier included in the connection request signal is stored in the IP address history DB 13. Here, the connection control module 11 confirms that the IP address history corresponding to the IP address history DB 13 is not stored. For example, when the communication terminal 20 is connected to the access point AP1 for the first time, or when a predetermined period or more has elapsed since the previous connection, the IP address history is not stored in the IP address history DB 13.

  Next, the connection control module 11 supplies an authentication request for the communication terminal 20 to the authentication module 12 (step S3). At this time, the connection control module 11 also notifies that the IP address history is not stored. The authentication module 12 verifies the validity of the terminal identifier acquired from the communication terminal 20 by comparing it with the terminal identifier stored in the subscriber information database. If the authentication is successful, the authentication module 12 issues an IP address and assigns it to the communication terminal 20 (step S4). The authentication module 12 issues an IP address that does not overlap with other communication terminals in the communication system 1 and is not stored in the IP address history DB 13. Here, it is assumed that the authentication module 12 issues and assigns an IP address A “203.138.ef”. The authentication module 12 notifies the communication terminal 20 of the IP address reassigned to the communication terminal 20.

  The communication terminal 20 stores the IP address assigned in the process of step S4, and thereafter uses it for communication with the first server 30 via the access point AP1. Through this communication, the first server 30 specifies that the IP address assigned to the communication terminal 20 is IP address A, and uses it as a destination address when transmitting a communication packet in push-type communication. Here, it is assumed that the gateway device 15 has received the communication packet pd1 in the push-type communication specifying the IP address A as the destination address from the first server 30 via the communication line L1. In this case, the gateway device 15 transfers the communication packet pd1 with the communication terminal 20 specified by the destination address as the transmission destination (step S5).

Next, when disconnecting the connection to the access point AP1, the communication terminal 20 transmits a disconnection request signal to the network 10 (step S6 in FIG. 6). For example, when the communication terminal 20 switches the connection destination from the access point AP1 to AP2, or when the connection with the network 10 is terminated, the disconnection request signal is transmitted. The disconnect request signal includes a terminal identifier assigned to the communication terminal 20, for example. When the connection control module 11 detects disconnection of the communication terminal 20, the connection control module 11 generates an IP address history in which the terminal identifier of the communication terminal 20 is associated with the IP address assigned to the communication terminal 20, and the IP address history DB 13. (Step S7). When the terminal identifier is “0903333 ***”, the connection control module 11 updates the IP address history DB 13 so as to have the configuration shown in FIG. That is, the connection control module 11 creates a new record in the IP address history DB 13 and stores the terminal identifier “0903333 ***” and the IP address A “203.138.ef” in association with each other. In the network 10, the IP address A assigned to the communication terminal 20 is discarded when the connection of the communication terminal 20 to the access point AP <b> 1 is cut off. However, IP addresses stored in the IP address history DB 13 are not assigned to other communication terminals.
Even when the connection control module 11 detects disconnection without receiving a disconnection request signal due to the battery running out of the communication terminal 20 or moving out of the communicable area, the process of step S7 The IP address history is stored in the IP address history DB 13.

  When the first server 30 transmits the communication packet pd2 having the IP address A as the destination address during the non-connection period after the connection between the communication terminal 20 and the access point AP1 is disconnected, the gateway device 15 receives this ( Step S8). In this case, the gateway device 15 supplies a reception notification for notifying the reception (incoming) of the communication packet to the connection control module 11 (step S9). This reception notification includes the IP address (here, IP address A) that is the destination address of the communication packet pd2. The connection control module 11 that has received the reception notification checks whether or not the IP address included in the reception notification matches the IP address history stored in the IP address history DB 13 (step S10). Here, the IP address A “203.138.ef” is stored in the IP address history DB 13 (see FIG. 8). In this case, the connection control module 11 supplies a communication packet transfer request to the gateway device 15 (step S11).

  The gateway device 15 that has received the transfer request supplies the communication packet pd2 to the data transfer module 14 (step S12). The data transfer module 14 buffers the communication packet pd2 received from the gateway device 15 (step S13). The data transfer module 14 continuously stores the buffered communication packet pd2 until the opportunity to transfer it to the communication terminal 20.

  Thereafter, in order to reconnect to the access point AP1, the communication terminal 20 transmits a connection request signal designating the APN that identifies the access point AP1 to the network 10 (step S14 in FIG. 7). Next, the connection control module 11 confirms the IP address history stored in the IP address history DB 13 based on the received connection request signal (step S15). Here, the connection control module 11 determines that the IP address history in which the terminal identifier “0903333 ***” of the communication terminal 20 is associated with the IP address A “203.138.ef” is the IP address history DB 13. Make sure it is saved in. Depending on the result of this confirmation, the connection control module 11 supplies an authentication request for the communication terminal 20 to the authentication module 12 (step S16). At this time, the connection control module 11 also notifies that the IP address history is stored in the IP address history DB 13.

  The authentication module 12 that has received the authentication request acquires the IP address of the communication terminal 20 stored in the IP address history DB 13 when the authentication of the communication terminal 20 is successful, and reassigns the IP address (step) S17). Specifically, the authentication module 12 determines that the IP address A “203.138.e.f” associated with the terminal identifier “0903333 ***” included in the connection request signal transmitted in the process of step S14. Is obtained from the IP address history DB 13 and this IP address A is assigned to the same communication terminal 20 again. The authentication module 12 notifies the communication terminal 20 of the reassigned IP address. The communication terminal 20 stores the IP address that has been reassigned in the process of step S17, and uses it thereafter for communication with the first server 30 via the access point AP1.

Next, the connection control module 11 supplies a transfer request for the buffered communication packet to the data transfer module 14 (step S18). This transfer request includes the IP address that has been reassigned in step S17. The data transfer module 14 that has received the transfer request performs a transfer process of transferring a communication packet having the IP address included in the transfer request as a destination address from the buffer to the communication terminal 20 (step S19). The communication terminal 20 receives the communication packet pd2 received by the gateway device 15 and buffered in the data transfer module 14 from the network 10 by this transfer process during the non-connection period.
Thereafter, in the communication system 1, the above-described processing is executed in accordance with a change in the connection state between the network 10 and the communication terminal 20.

  In the communication system 1 according to the first embodiment described above, when the network 10 assigns an IP address to the communication terminal 20 connected to the access point AP1, the network 10 stores the communication terminal 20 assigned the IP address in an identifiable manner. deep. When the communication terminal 20 disconnects from the access point AP1 and reconnects after a non-connection period, the network 10 reassigns the stored IP address to the same communication terminal 20. By this reassignment, the IP addresses assigned to one communication terminal 20 are the same before and after the non-connection period. Therefore, even if the network 10 transfers the communication packet generated during the non-connection period later, push-type communication performed with respect to the communication terminal 20 can be established.

[Second Embodiment]
A second embodiment of the present invention will be described.
The communication system 1 of this embodiment does not transfer a communication packet generated during a non-connection period between the communication terminal 20 and the access point AP1 while waiting for an opportunity for the communication terminal 20 to reconnect to the access point AP1, instead of transferring the communication packet. It differs from the first embodiment described above in that the communication packet is transferred by performing control to reconnect to the point AP1. The overall configuration of the communication system 1 may be the same as the configuration described in FIG.
Hereinafter, differences from the configuration and operation of the first embodiment described above will be mainly described, and the same configurations as those of the first embodiment described above will be denoted by the same reference numerals, and description thereof will be omitted as appropriate. .

FIG. 9 is a block diagram showing the configuration of the network 10. FIG. 9 is a block diagram of a network management system that manages communication performed between the communication terminal 20 and the first server 30 in the network 10.
As illustrated in FIG. 9, the network 10 includes a state determination module 16 instead of the data transfer module 14 described in the first embodiment. In addition, the connection control module 11 realizes a function of controlling the connection state between the network 10 and the communication terminal 20 instead of the function related to the data transfer module 14 described in the first embodiment.

When the connection between the access point AP1 and the communication terminal 20 is disconnected, the connection control module 11 transitions the connection state to the preservation state. The preservation state refers to a state in which a connection in a wireless section is released while a communication path (that is, a session) is maintained. Further, when a communication packet addressed to the communication terminal 20 is generated during a non-connection period with the access point AP1, the connection control module 11 returns from the reservation state and restarts the connection in the wireless section.
The state determination module 16 is a module that determines whether or not the access point AP1 and the communication terminal 20 are in a preservation state. The state determination module 16 may request the connection control module 11 to return from the preservation state.

Next, the operation of the communication system 1 will be described.
10 and 11 are sequence diagrams illustrating the flow of processing executed in the communication system 1. FIG. 10 shows a flow of processing when the communication terminal 20 is connected to the network 10 and an IP address issued by the network 10 is assigned to the communication terminal 20. The flow of this process may be the same as steps S1 to S5 of the first embodiment described above, and the description thereof is omitted.

  Next, when the communication terminal 20 disconnects the connection with the access point AP1 and connects to the access point AP2, the communication terminal 20 transmits a disconnection request signal to the network 10 (step S21 in FIG. 11). By disconnecting the connection, the connection control module 11 changes between the access point AP1 and the communication terminal 20 to the preservation state.

  When detecting the transition to the preservation state, the connection control module 11 supplies a notification to that effect to the state determination module 16 (step S22). The state determination module 16 that has received this notification determines that the state between the access point AP1 and the communication terminal 20 is in the preservation state. In addition, the connection control module 11 stores, in the IP address history DB 13, an IP address history in which the terminal identifier of the communication terminal 20 that has transitioned to the preservation state is associated with the IP address assigned to the communication terminal 20 ( Step S23). Here, as in the first embodiment described above, the connection control module 11 updates the IP address history DB 13 so as to have the configuration shown in FIG.

  Then, when the first server 30 transmits the communication packet pd2 designating the IP address A as the destination address during the non-connection period to the access point AP1 after the transition to the preservation state, the gateway device 15 receives this. (Step S24). Next, the gateway device 15 confirms with the state determination module 16 that the connection state with the communication terminal 20 to which the same IP address as the destination address of the communication packet pd2 is assigned is the preservation state. In this case, the gateway device 15 supplies a request for return from the preservation state to the state determination module 16 (step S25). The state determination module 16 that has received the return request supplies a return request from the preservation state to the connection control module 11 (step S26). The connection control module 11 that has received the return request transmits a return signal as a control signal for returning from the preservation state to the communication terminal 20 (step S27). In response to the received return signal, the communication terminal 20 switches the connection destination from the access point AP2 to the access point AP1 so as to return from the reservation state (step S28).

  Next, the connection control module 11 confirms the IP address history stored in the IP address history DB 13 for the communication terminal 20 that has been restored from the preservation state (step S29). Similar to the processing in step S15 of the first embodiment described above, here, the connection control module 11 determines the terminal identifier “0903333 ***” of the communication terminal 20 and the IP address A “203.138.ef”. Is confirmed to be stored in the IP address history DB 13. Next, the connection control module 11 supplies an authentication request for the communication terminal 20 to the authentication module 12 (step S30). When the authentication request is received and the communication terminal 20 is successfully authenticated, the authentication module 12 acquires the IP address of the communication terminal 20 stored in the IP address history DB 13 and reassigns the IP address ( Step S31). Specifically, the authentication module 12 assigns the IP address A “203.138.ef” to the communication terminal 20 again.

Next, the connection control module 11 notifies the state determination module 16 that it has returned from the preservation state (step S32). In response to this notification, the state determination module 16 supplies a communication packet transfer request to the gateway device 15 (step S33). This transfer request includes the IP address that has been reassigned in the process of step S31. The gateway device 15 that has received the transfer request performs a transfer process of transferring a communication packet having the IP address included in the transfer request as a destination address to the communication terminal 20 (step S34). The communication terminal 20 receives the communication packet pd2 from the network 10 by this transfer process. That is, in the second embodiment, the gateway device 15 realizes a function as a transfer processing unit.
Thereafter, in the communication system 1, the above-described processing is executed in accordance with a change in the connection state between the access point AP1 and the communication terminal 20.

  Also in the communication system 1 of the second embodiment described above, the network 10 assigns the same IP address to one communication terminal 20 before and after the non-connection period. By this IP address assignment, the network 10 can establish push-type communication under the initiative of the network. In the second embodiment, the network 10 restores the connection state between the communication terminal 20 and the access point AP1 from the reservation state when the communication packet is received. As a result, it is possible to quickly transfer communication packets in push-type communication to the communication terminal 20 as compared with the case where the process of connecting the communication terminal 20 and the access point AP1 is started from scratch.

[Modification]
The present invention can be implemented in a form different from the above-described embodiment. The present invention can also be implemented in the following forms, for example. Further, the following modifications may be combined as appropriate.
In the first embodiment described above, when the communication terminal 20 is disconnected from the access point AP1, the network 10 waits for the communication terminal 20 to reconnect and transfers the buffered communication packet. We were processing. Further, the network 10 may control the communication terminal 20 to reconnect to the access point AP1 and transfer the buffered communication packet when the capacity of the buffered communication packet increases beyond a threshold value. .

Specifically, the data transfer module 14 monitors the capacity of the buffered communication packet, and supplies a capacity excess notification to the connection control module 11 when the monitored capacity is equal to or greater than a threshold value. This threshold is determined based on, for example, the buffered communication packet capacity for each communication terminal 20. The connection control module 11 that has received the capacity excess notification transmits to the communication terminal 20 a control signal for reconnection to the access point AP1. For example, the connection control module 11 causes the communication terminal 20 to switch the connection destination using a control type SMS (Short Message Service). When the connection control module 11 detects reconnection to the access point AP1 by the communication terminal 20, the network 10 performs the above-described steps S15 to S18. Then, the data transfer module 14 transfers the buffered communication packet after being reconnected to the access point AP1 according to the control signal in the process of step S19.
According to the communication system 1 of the first modification, it is possible to prevent a large amount of buffered communication packets from being accumulated on the network 10 side.
Note that when switching the connection destination access point of the communication terminal 20, the connection control module 11 transmits a message prompting the switching by using, for example, an SMS service, and the like, and the user of the communication terminal 20 is notified of the connection destination. Switching may be prompted.

The modules provided in the network 10 described in the above-described embodiments, the processes executed by the modules, and signals exchanged between the modules are merely examples, and some of them may be omitted or replaced. For example, the connection control module 11 may store the IP address history in the IP address history DB 13 when the communication terminal 20 is successfully authenticated.
The network 10 is not limited to a wireless communication network, and may be a fixed communication network, and the communication method is not particularly limited.
Communication terminal 20 may selectively connect to three or more different access points in data communication.
In the communication system 1, push-type communication may be performed via two or more access points (connection destinations) to which the communication terminal 20 is connected. In this case, the network 10 manages communication packets generated during the non-connection period for each access point where push-type communication is performed.

  Each function realized by the network 10 of the above-described embodiment may be realized by one or a plurality of hardware circuits, or may be realized by an arithmetic device executing one or a plurality of programs. It may be realized by a combination. When the function of the network 10 is realized using a program, this program includes a magnetic recording medium (magnetic tape, magnetic disk (HDD (Hard Disk Drive), FD (Flexible Disk)), etc.), optical recording medium (optical disk, etc.). ), May be provided in a state of being stored in a computer-readable recording medium such as a magneto-optical recording medium or a semiconductor memory, or may be distributed via a network. The present invention can also be understood as a network management method performed by a computer.

DESCRIPTION OF SYMBOLS 1 ... Communication system, 10 ... Network, 11 ... Connection control module, 111 ... Storage part, 12 ... Authentication module, 121 ... 1st allocation part, 122 ... 2nd allocation part, 13 ... IP address history DB, 14 ... Data transfer module 141... Buffer processing unit 142... Transfer processing unit 15. Gateway device 16. State determination module 20. Communication terminal 30 30 First server 40 40 Second server

Claims (6)

A network management system for managing communication performed via an access point provided in a predetermined network,
When a communication terminal is connected to the access point, a first allocating unit that issues an IP (Internet Protocol) address that identifies a transfer destination of a communication packet and assigns the communication terminal to the communication terminal;
A storage unit that stores the IP address assigned by the first assigning unit so that the communication terminal to which the IP address is assigned can be identified;
A second allocating unit that reallocates the IP address stored by the storage unit to the communication terminal when the communication terminal disconnects from the access point and resumes the connection after a non-connection period; When,
When a communication packet having the destination address as the IP address assigned by the first assigning unit is generated during the non-connection period, the second assigning unit reassigns the IP address, and then the communication A network management system comprising: a transfer processing unit that transfers packets. A buffer processing unit for buffering communication packets generated during the non-connection period;
The transfer processing unit
The network management system according to claim 1, wherein a communication packet having the destination address as the IP address that has been reassigned by the second assigning unit is transferred from the buffer to the communication terminal. A connection control unit for transmitting a control signal for resuming the connection to the communication terminal when the capacity of the buffered communication packet is equal to or greater than a threshold;
The transfer processing unit
The network management system according to claim 2, wherein the buffered communication packet is transferred after the connection is resumed according to the control signal. A connection control unit that transitions the state of the connection to a preservation state when the connection is disconnected, and returns from the preservation state when a communication packet is generated during the non-connection period;
The transfer processing unit
The network management system according to claim 1, wherein the communication packet is transferred after returning from the preservation state. The network management system according to any one of claims 1 to 4, provided in the network;
A communication system comprising: a communication terminal connected to the access point and communicating with the network. A network management method for managing communication performed via an access point provided in a predetermined network,
When a communication terminal is connected to the access point, issuing an IP address that identifies a transfer destination of the communication packet and assigning the communication terminal to the communication terminal;
A storage unit for storing the assigned IP address so that the communication terminal to which the IP address is assigned can be identified;
Re-assigning the stored IP address to the communication terminal when the communication terminal disconnects the connection to the access point and restarts the connection after a non-connection period;
A network management method including a step of transferring the communication packet after reassigning the IP address when a communication packet having the assigned IP address as a destination address occurs during the non-connection period.

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